/*
 * Copyright (C) 2012 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package interactivespaces.service.script.internal;

import interactivespaces.InteractiveSpacesException;
import interactivespaces.service.script.Script;
import interactivespaces.service.script.ScriptSource;

import java.util.Map;

import javax.script.Bindings;
import javax.script.Compilable;
import javax.script.CompiledScript;
import javax.script.ScriptException;
import javax.script.SimpleBindings;

/**
 * A {@link Script} for compiled scripts.
 * 
 * @author Keith M. Hughes
 */
public class CompiledScriptScript implements Script {

	/**
	 * The engine for compiling the scripts.
	 */
	private Compilable compileEngine;

	/**
	 * Source for the script.
	 */
	private ScriptSource scriptSource;

	/**
	 * The compiled script.
	 */
	private CompiledScript script;

	public CompiledScriptScript(Compilable compileEngine,
			ScriptSource scriptSource) {
		this.scriptSource = scriptSource;

		try {
			script = compileEngine.compile(scriptSource.getScriptContents());
		} catch (ScriptException e) {
			throw new InteractiveSpacesException("Could not compile script", e);
		}

	}

	@Override
	public Object eval(Map<String, Object> bindings) {
		Bindings myBindings = new SimpleBindings(bindings);
		try {
			if (scriptSource.isModified()) {
				script = compileEngine
						.compile(scriptSource.getScriptContents());
			}

			return script.eval(myBindings);
		} catch (ScriptException e) {
			throw new InteractiveSpacesException("Could not evaluate script", e);
		}
	}
}
